Field of the Invention
The invention relates to a method and an apparatus for introducing a self-propelled in-pipe manipulator into a pipeline.
Pipelines in system parts relevant to safety, such as the primary loop of a nuclear power plant, must be inspected and maintained at regular intervals. In particular, regulation inspection of weld seams on the insides of such pipelines is necessary. The equipment used for the inspection or the work is put into an inspection or machining position by self-propelled vehicles, as a rule.
Such self-propelled in-pipe manipulators are known, for instance, from German Patent DE 34 12 519 C2. That patent discloses an in-pipe manipulator in which a radially adjustable inspection system carrier is disposed between two support surfaces. It can be rotated about the longitudinal axis of the in-pipe manipulator and in that way enables inspection of the inner surface of the pipe over its entire circumference.
European Patent 0 204 694 B1 discloses an in-pipe manipulator in which a machining device on a chassis that can be driven on wheels is supported in a revolving shackle that is disposed on an L-shaped bearing rotatably supported on an end surface of the vehicle.
When pipelines are inspected or machined, a problem which arises among others is that the weld seams to be inspected or machined may be located immediately behind an opening through which the in-pipe manipulator has to be introduced into the pipe. In principle, such weld seams located directly at the pipe opening cannot be detected by the in-pipe manipulator that is known, for instance, from German Patent DE 34 12 519 C2, because that in-pipe manipulator is not ready for use until both of its two support flanges have been positioned all the way into the pipe. In the device known from European Patent 0 204 694 B1, it is indeed possible to inspect or machine in the peripheral region of a pipe, but under some circumstances that requires turning the in-pipe manipulator around and introducing it into the pipe facing in the opposite direction, if inspection or work positions at the beginning and ending regions of a pipe are to be detected.